Function d3_acos

explainshell/web/static/js/d3.v3.js:1287–1289

(x)

    return x > 0 ? 1 : x < 0 ? -1 : 0;
  }
  function d3_acos(x) {
    return Math.acos(Math.max(-1, Math.min(1, x)));
  }
  function d3_asin(x) {
    return x > 1 ? π / 2 : x < -1 ? -π / 2 : Math.asin(x);
  }